diff options
Diffstat (limited to 'llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp')
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp b/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp index a4d84ae81aa..ee30aa44674 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp @@ -169,6 +169,18 @@ isOnlyCopiedFromConstantGlobal(AllocaInst *AI, return nullptr; } +/// Returns true if V is dereferenceable for size of alloca. +static bool isDereferenceableForAllocaSize(const Value *V, const AllocaInst *AI, + const DataLayout &DL) { + if (AI->isArrayAllocation()) + return false; + uint64_t AllocaSize = DL.getTypeStoreSize(AI->getAllocatedType()); + if (!AllocaSize) + return false; + return isDereferenceableAndAlignedPointer(V, AI->getAlignment(), + APInt(64, AllocaSize), DL); +} + static Instruction *simplifyAllocaArraySize(InstCombiner &IC, AllocaInst &AI) { // Check for array size of 1 (scalar allocation). if (!AI.isArrayAllocation()) { @@ -390,7 +402,8 @@ Instruction *InstCombiner::visitAllocaInst(AllocaInst &AI) { if (MemTransferInst *Copy = isOnlyCopiedFromConstantGlobal(&AI, ToDelete)) { unsigned SourceAlign = getOrEnforceKnownAlignment( Copy->getSource(), AI.getAlignment(), DL, &AI, &AC, &DT); - if (AI.getAlignment() <= SourceAlign) { + if (AI.getAlignment() <= SourceAlign && + isDereferenceableForAllocaSize(Copy->getSource(), &AI, DL)) { DEBUG(dbgs() << "Found alloca equal to global: " << AI << '\n'); DEBUG(dbgs() << " memcpy = " << *Copy << '\n'); for (unsigned i = 0, e = ToDelete.size(); i != e; ++i) |
